| Electric load simulator is used to simulate the load characteristic of rudder’s servo mechanism when aircrafts are in flight, which is loaded by motor. It provides the dynamic loading experiment condition of the real load object in product performance acceptance test, lift test. Electric load simulator is a typical passive force control system. Loading motor must complete accurate torque output when follows the position changes of the rudder motor passively. The active movement of the rudder sever actuator will generate position disturbance torque. Position disturbance torque is the main factor that makes the torque output of loading motor not follow the given torque curve. Electric load simulator is made to be the research object. This paper is to study the key problem of how to eliminate position disturbance torque.Firstly, the mathematical model of the electric load simulator is established, using a permanent magnet synchronous AC servo motor. On the basis, the characteristics of the rudder servo system, loading system and extraneous force in frequency and time domain are analyzed. Then the formation mechanism and characteristic of extraneous force are explained, which can provide theoretical support for eliminating position disturbance torque.The Feed-forward compensation method is proposed to eliminate the extraneous force, and discuss the controller design separately when use the position output signal of the rudder servo actuator and the angular velocity output signal of the loading motor as feed-forward compensation signal. The simulated result shows that the feed-forward compensation can eliminate disturbance torque effectively. But applied in practical system, the noise signal of the senor acquisition signal will influence the compensation’s effect. So propose to use the given position signal of rudder servo system as the input signal of feed-forward compensation controller. Then tuning amplitude and tuning frequency is added into controller to get the efficient compensation signal. In view of the feed-forward compensation having the problem of poor robustness and adaptive ability, the fuzzy-PID controller is applied and The simulated result shows that which can eliminate disturbance torque effectively.At last, the hardware and software structure of electric load simulator are designed.The experimental result show that position disturbance torque has been eliminated when using the feed-ward compensation controller. |
